Pumping device



Dec. 16, 1958 V P. A. ROBINSON 2,864,317

' PUMPING DEVICE Filed Oct. 5, 1953 2 Sheets-Sheet 1 F -44 m2 4 i g l 54 5a 52 a flrfozv Dec. 16, 1958 P. A. ROBINSON 2,864,317

PUMPING DEVICE Filed 001;. 5, 1953 2 Sheets-Sheet 2 Unite Sttes Patent Ofiice 2,864,131 7 Patented Dec. '16, 1958 PUMPING DEVICE Parnell A. Robinson, Los Angeles, tlalif.

Application October 5, 1953, Serial No. 384,236

14 Claims. (Cl. 103-235) My present invention relates to pumps for pumping water, oil or other liquids from one level up to a higher level, such as for pumping liquids out of deep Wells, and it relates particularly to pressure differential pumping devices for pumping liquids from one level to a higher level.

It is well known in the art to pump liquids, such as water and oil, from one level to another level, by applyinga partial vacuum to a tubular pumping device. However, all of the prior art vacuum pumps with which the applicant is familiar are only capable of pumping fluid to av height which will cause the column of fluidto exert a pressure that is less than the pressure exerted by the atmosphere. In; Prior art vacuum pumping devices, if the column of liquid to be pumped has a height which is equal to or greater than that which wouldexert a pressure equal to atmospheric pressure, then moving parts are required down within the well.

Therefore, the principal object of my present invention is to provide a vacuum pumping device which is capable of pumping a liquid to any height by the mere application of a partial vacuum to the top of the pump string without the requirement of any moving parts in the pumping string.

Another object of my present invention is to provide a vacuum-type pumping device in which the pump string can be inserted to any depth within a well to permit the removal of fluid from thewell by the mere application of a partial vacuum at the top of the pump string.

Another object of my invention is to provide a vacuum type pumping device which is capable of pumping a column of fluid that ismuch greater in height than a column of the fluid which would exert a pressure that is substantially equal to the pressure exerted by the atmosphere, without any apparent diminishing of the rate of flow of the fluid at the top of the pumping device as i the length of the pump string is increased.

Another object of my invention is to provide a vacuum type pumping device of the character described'in which the pump string is relatively narrow in diameter, occupying a minimum of space in any well in which the pumping device is operated.

A further object of my invention is to provide a pumping device of the character described which consists of a plurality of joining sections that are relatively short in length and that are connected together by means of a plurality of hose sections in order to provide a relatively inexpensive pumping device which is convenient to market and to store.

Another object of my present invention is to provide a pumping device in which the pump string may be conveniently and economically made of plastic.

Another object of my present invention is to provide a pressure diflerential pumping device in which a relatively low pressure differential may be employed to pump fluid regardless of the height to which the fluid is pumped.

Other objects of my present invention will be apparent 2 a from the following description and claims, thenoveltyof my invention consistingin the features of construction, the combinations of parts, the novel relations ofthe members and the relative proportioning, disposition and operation thereof, all as is more completely described herein and as more particularly pointed out in vthe aplpended claims.

In the accompanying drawings, forming a part of my present specification, I

Figure 1 is an elevational view of my preferred embodiment,

Figure 2 is a vertical section ofmy preferredembodiment with portions broken away to'illustrate several stages of my pump string, Figure 3 is a horizontal section of my prefer-redembodiment taken along the line 3-3 in Figure 2, Figure 4 is a horizontal section of my preferred embodiment taken along the line 44 in Figure 2, Figure 5 is an exploded perspective view of an alternative embodiment of my invention, and

Figure 6 is a vertical section illustrating two of my joining sections for my alternative embodiment illus? trated in Figure 51- i Referring to my drawings, I provide a vacuum pump 10 whichis operatively connected to'a reservoirf'12's'o that gases may be evacuated from re:ervoir 12. A primary vacuum line 14 is connected to the upper portion of reservoir 12, and divides into two secondary vacuurn lines 16 and 18, which are operatively connected to th'e top of my pump'string 20in the manner hereinafter more fully described in connection with Figure 2 ofthe drawings.

Although my pump string 20 may include any number of pump sections, I have illustrated a pumpstring 20 which includes three sections 22;, 24 and 26 in Figures 1 and 2 of the drawings. Although pump sections 22, and 26 maybe operatively connected to form the entire pump string 20 in any desiredirn anner, a preferred m s of attaching the pump sections 22 24 and, 2Qtog ethen1s by the use of coupling sleeves 28. p y;

Referring particularly to FiguresZ, 3 and.4, rn yypunip string 20 generally consists of a cylin drical outershell member 30 within .Which are disposed a pluralit smaller tubes. In my preferred embodime npf a tre tively large reservoir tube 32 ,and a pair of smallerpumping tubes 34 and 36 are provided. Although these lthree tubes may have any desired cross-sectional shap I prefer to provide pumping tubesl land 35 whic h e circular cross-sections, and a reservoir tube which has a generally parabolic cross-section, so thatthesethree u e 2 34 and 36, ma 1 0 t isntlrfit With nth preferably circular cross-section of the outer. shell me' ber 30. Althougho ther relativetsiz'es between reservoir tube 32 on the one hand and pumping tubes.3,4 and 335 on the other hand may be used, I have foundthatapreferred relationship of the areas of, these tubes is a .6] square unit cross-sectional area for each of the smaller tubes 34- and 36 to a ,93 square unit cross-sectional, area for reservoir tube 32. e

In my preferred embodiment I provide a pair of vacuum or low pressure tubes 38-and 40, which need not have smooth internal contours, the tops of which are operatively connected to the secondary vacuum lines 16 and 18, respectively. Although it is most convenientto use two vacuum tubes, such as tubes 38 and 40, in my preferredembodiment, other embodimentsof my invention may require only a single such vacuum tube, such as my alternative embodimentillustrated in Figures 5' and 6 of the drawings. Z i The remaining tube which is included within cylindrical outer shell member Stlis the vacuum relief or high 20 is lowered into the well or is otherwise immersed in the liquid to be pumped so that the liquid covers the bottom end 49 of pump string 20. Bottom plugs 50 and 52 seal off the bottom ends of reservoir tube 32 and pumping tube 34, respectively. The liquid enters the bottom end 49 of pump string 20 through the open lower end 54 of pumping tube 36, the liquid being lifted by the application of a partial vacuum to the inside of'pumping tube 36 through vacuum port 56 which is connected to vacuum tube 40. A plug 57 is disposed just above vacuum port 56 within pumping tube 36.

The liquid is thus raised within pumping tube 36 until it reaches a relatively large flow passage 58 which permits the liquid to flow into chamber 60 within reservoir tube 32, chamber 60 being defined between bottom plug 50 and a plug 62 in reservoir tube 32 adiacent to plug .57 in umping tube 36. A preferred height for chamber 60 is approximately 8 feet, although chamber 60 may be of greater or lesser height depending on the amount of vacuum applied to the system. I prefer to place p ssage 58 about three-fourths of the way up from the bo t m of chamber 60.

Chamber 60 then becomes about three-quarters filled with water, and a column of water of about the same height fills pumping tube 34 above plug 52, this liquid flowing into pumping tube 34 through a relatively large .flow passage 64 iust above plugs 50 and 52 at the bottom of the pump string 20.

Vacuum relief tube 42 opens into pumping tube 34 just above bottom lug 52 through a tube 66 at vacuum relief ort 68. Although I prefer to place vacuum relief port 68 at the end of a tube 66. vacuum relief port 68 may actually consist of an opening near the lower end of pum ing tube 34.

N zz e 68 is preferably disposed above flow passage 64 in order to prevent backing up of the .fluid being pumped due to oscillation set up by the bubble action hereinafter described.

I prefer to provide a tube 66 having a substantially greater diameter than nozzle 68 in order to provide a sufficient q antity of air adjacent to nozz e 68 to permit the rapid release of bubbles from nozzle 68. i

A gas bubble 69 forms at regular intervals in pumpiing tube 34 just above plug 52 by the passage of gas from vacuum relief tube 66 out through port 68. Bubble 69 quickly hoists the li uid above it upwardly pumping tube 34 until the liquid flows laterally through flow passa e 74 into the next higher chamber 76 in reservoir tube 32 which is defined between plugs 62 and 78 which ,are referably spaced about 8 feet apart.

Adjacent to plug 78 in reservoir tube 32, a plug 72 is disposed in pumping tube 34. Just below plug 72 is a vacuum port 70 which is operatively connected to vacuum tube 38. In addition to the action of bubbles 69 in moving the liquid up from flow passage 64 to flow passage 74, suction applied to pumping tube 34 through vacuum port 70 will hoist the liquid upwardly through pumping tube 34. All of the spaced gas bubbles 69 will, of course, be removed from pumping tube 34 through vacuum port 70 into vacuum tube 38 and thereby none of the bubbles 69 will be permanently mixed with the liquid so as to areate the liquid or cause a foam or otherwise interfere with the pumping operation.

After the, fluid has flowed into chamber 76 through flow passage 74, which is preferably about three-quarters of the way up from the bottom of chamber 76, this fluid then flows through a flow passage 80 at the bottom of chamber 76 into pumping tube 36. This fluid is then hoisted upwardly through pumping tube 36 in the same manner that the fluid was hoisted from passage 64 to passage 74 through pumping tube 34. Thus, gas bubbles are periodically released into pumping tube 36 just above plug 57 through vacuum relief port 84 at the end of a tube 82 which is connected to vacuum tube 40. Also, suction is applied in pumping tube 36 through vacuum port 86 which connects pumping tube 36 to vacuum tube 40 just below a plug 88 in pumping tube 36.

The fluid thus lifted through pumping tube 36 then flows through passage 90 into another chamber 92 in reservoir tube 32. Chamber 92 is again preferably about eight feet in length, and has its upper end defined by a plug 94 disposed adjacent to the plug 88 in pumping tube 36. Passage 90 is preferably about two-thirds of the distance between plugs 78 and 94.

The fluid then flows laterally through passage 96 just above plugs 78 and 72 into pumping tube 34, and the fluid is raised in pumping tube 34 by means of bubbles which are released from vacuum relief port 100 at the end of a tube 98 which is connected to vacuum relief tube 42.

I provide a header 102 defined by outer shell member 30, plugs 88 and 94, and a top plug 103. Header 102 is operatively connected to the central portion of reservoir 12 bymeans of a fluid conduit 104. The partial vacuum applied within header 102 through conduit 104 from reservoir 12 assists in raising the liquid into header 102 and transferring the liquid from header 102 into reservoir 12.

If it is desired, header 102 may be eliminated, and fluid conduit 104 may be connected directly to the top of pumping tube 34.

The fluid thus pumped into reservoir 12 may then be removed for use through a fluid outlet pipe 106 from the bottom of reservoir 12.

Although Figure 2 illustrates my invention with several pumping stages, my pump string may consist of only a single stage in which the fluid enters the string in the usual manner at the open lower end 54 of pumping string 36 with the assistance of the partial vacuum applied through vacuum port 56, the fluid then passing through passage 58 into chamber 60 and then through passage 64 into pumping tube 34. Instead of the additional chambers 76 and 92 and their associated flow passages, pumping tube 34 is connected directly to header 102 or to fluid conduit 104. Fluid may be pumped considerably higher by this single stage' of my invention than it could be with an ordinary vacuum pump using a comparable vacuum.

My preferred pumping device includes a closed gas system, instead of merely utilizing air which would enter the system through vacuum relief tube 42 and be pumped out of the system by vacuum pump 10. This is for the reason that the use of air in some pumping operations would cause an explosion hazard, so that the use of an inert gas, such as nitrogen, helium or the like, is preferable. This closed system is effected by a connection between vacuum relief tube 42 and the exhaust port of vacuum pump 10, this connection including vacuum relief line 44 and vacuum relief reservoir 46. Since the only gas which enters the pump string 20 enters through vacuum relief line 44, and all of this gas which thus enters pump string 20 is removed through vacuum tubes 38 and 40, and the corresponding secondary vacuum lines 16 and 18 which connect together into primary vacuum ;line- 14, no air will be permitted to enter the system, and

none of the inert gas used will be permitted to escape.

If the particular use of my pumping device does not require an inert gas, such as when my pumping device is used for pumping Water out of a well, the above-describedclosed gascircuit is not essential, and the operatiye connection shown in Figure 1 between vacuum relief tube 42 and the output port of vacuum pump may be eliminated, so that air will be permitted to enter vacuum relief tube 42 from the atmosphere.

I will now describe my preferred method of operating my preferred embodiment shown in Figures 1, 2, 3, and 4 of the drawings. The first step is to lower the pump string 20 to the desired depth into the well. Any number of the pump sections22, 24 and 26 may be used, according to the depth of the well, and without regard to whether or not the length of the column of liquid pumped is greater than the height of a column of the same. liquid which will be required to balance atmospheric pressure. If it is desired, the sections 22, 24 and2'6 may be provided separately and may. be joined together either just before the pump string 20 is lowered into the well or as it is being lowered into the well. This may be accomplished by externally threading the ends of the various pump sections 22, 24 and 26, and internally threading coupling sleeves 28, with suitable sealing washersbeing provided at the open ends of the various tubeswithin the individual pump sections 22, 24 and 26.

After thepump string 20 has thus been lowered into the well, and vacuum pump 10 and reservoir 12 coupled thereto in the manner illustrated in Figure 1 of the drawings, vacuum. pump. 10 is then turned on to commence the pumping operation.

' The amount of. suction applied invacuum tubes 38 and'4tlmay be adjusted either by adjustment of vacuum pump 10, or by adjustment of a valve 108 disposed. in vacuum line 14; The setting of vacuum pump 10 or of valve 108 in line 14 will be determined by the rate offluid flow desired, andby the height of the individual pump sections 22, 24 and 26', longer individual sections 22, 24 and 26 requiring a higher vacuum in order to properly pump the liquid. The rate of flow of the liquid into reservoir 12 may be independently regulated, regard.- less of the amount of vacuum applied to vacuum, tubes 38'and 40, by adjustment, of a valve 110 disposedin fluid conduit 104.

A valve 112' disposed in vacuum relief line 44 permits the regulation of the gas pressure within vacuum relief tube 42 to provide the optimum rate of bubble production through vacum relief ports 68, 84 and 100. Normally, the gas pressure Within vacuum relief tube 42 will. be below atmospheric pressure, although this is not necessarily the case.

If the closed gas system illustrated in Figure 1 of the drawings is not used, then a valve 112is preferably still embodied in vacuum relief line 44 which would then connectvacuum relief tube 42 to the atmosphere, in order to adjust the gas pressure within vacuum relief tube 42 to. provide the optimum rate of bubble production. If vacuum. relief line 44 is not provided with a valve- 112, then the orifice sizes of vacuum relief ports 68, 84 and 1110 are such that the optimumrate of bubble production will be caused.

The liquid is then raised through the pump string 20 by first being raised into the lower portion of pumping tube 36 by suction from vacuum port 56 and then flowing through lateral passage 58 into reservoir chamber 60. Then the fluid flows out of reservoir chamber 611 through passage 64 at the bottom thereof into pumping tube 34, through which the liquid is raised by means of bubbles 69- released from vacuum relief port 68 and by suction applied through vacuum port 70, the liquid then flowing laterally through passage 74 into a second reservoir chamber 76. Next,.the fluid flows through passage, 80 at the bottom of the second reservoir chamber 76 into pumping tube 36, through which the liquid is raised by bubbles from vacuum relief port 84 and by suction from vacuum port 86, this fluid flowing laterally through a passage 90 into the third reservoir chamber 92, from which it passes through a passage 96 into pumping tube 34, to be raised again by bubbles from vacuum relief port 1011 and. by suction applied at the'top of pumping tube 34. V

This pumping process, although herein illustrated only in connection with three pump sections, 22,24, and 26, may be carried on in the same manner for any number of pump sections.

The purpose of reservoir chambers 60,76 and 92' is two-fold. First, these chambers at all times contain sufficient liquid so that the passages 64, and 96' at the respective bottoms thereof are at all times submerged in the liquid, regardless of the pulsating efifect caused by the intermittent introduction of bubbles through vacuum relief ports 68, 84. and 100. This prevents any interference with the eflicient operation of the bubbles.

The second function, of reservoir chambers 60; .6. and 92 is the provision of a cushioning effect against the pulsating in the system caused by thebubblesthe cushion being provided by the gas space, at the top of each of the reservoir chambers 60,. 76 and 92} if pump, string 20 is built up by individual sections such as 22,24 and 26 to such aheightthat alarge amount of frictionloss appears in vacuum tubes-38 and 40,, an additional vacuum tube (not shown) may be embodied-in the pump string to, accomplish the functions of tubes 38 and 40; for the upper portion of pump string, 20.,

Although I haveshown-and described a preferred. embodiment, of my inventionin which. the various tubes. are all contained withina cylindrical outer shell member, 30, it is to be understood that separate, generally rigid, tubes may be operatively connected together in above-described manner without the use of an outer shell. Insuch an em; bodiment of my invention; it would generally be prefer,- able to use a single vacuum tube rather than the two vacuum. tubes 38 and 40 shown in Figures. 3' and. 4, ofthe drawings.

In Figures 5, and 6 of the drawings I have illustrated an alternativeembodiment. of my present invention which briefly consists of a plurality of joining sections, such as joining sections 114 and 116, which are joined. together by means. of a plurality of hose sections, such, as, hose sections 148,164, 176, 194 and 196.

This alternative; embodiment of my invention operates in exactly the same manner asimy preferred embodiment of Figures 1- to 4, and is connected at itsupper end to vacuum pump 10 and reservoir 12. in the same manner as my preferred embodiment. trateda single complete section in Figures 5 and 6, with portions of the upper and lower adjoining sections also being shown in order to clearly disclose the manner in which the various parts are operatively inter-connected. Each of the joining sections 114 and 116 may be made of, plastic, metal or other suitable material, and preferably has a cross-sectional shape that is identical with the cross-sectional shape of the preferred embodiment of my invention as is best illustrated in Figure 3 of the drawings. Thus, each'of the joining sections 114 and 116 preferably has relatively large reservoir tube 118, a pair of preferably circularly cross-sectioned pumping tubes 120 and 122, a pair of vacuum or low pressure tubes 124-and 126, and a vacuum relief or high pressure tube 128. Joining sections 114 and 116 are preferably each about two feet in length, although this length is not critical.

Fluid will be lifted upwardly through hose section 129 and nozzle 130 into pumping tube 122 by means of suction applied in pumping tube 122 of joining section 116 through vacuum port 132 disposed just below a plug 134. If the next joining section below joining section 116 is the bottom section, then the liquid will have been lifted up into joining section 116 solely by suction applied through vacuum port 132. However, if the next join ing section below joining section 116 is merely an intermediate joining section, then the liquid will have been lifted up into joining section 116 through nozzle 130both by Thus, I have only illus-' .suction applied through vacuum port 132 and by means of a bubble released in the lower joining section. The liquid thus hoisted into joining section .116 then passes laterally through .a passage 136 into reservoir Chamber 138 having its upper end defined by a plug 140. Passage 136 corresponds to passage 58 in the preferred embodiment of my invention as illustrated in Figure 2, and chamber 138 corresponds to chamber 60 of my preferred embodiment. The lower portion of chamber 138 is operatively connected to the upper portion of chamber 138 within joining section 116 by means of nozzle 142, the lower portion of chamber 138 consisting ofhose section 143, together with a reservoir tube portion of the next'lower joining section (not shown), this lower reservoir tube portion of chamber 138 being identical in construction to chamber 184 in joining section 114.

The liquid which is thus pumped into reservoir chamber 138 then passes through a, lateral passage in the joining section below section 116 which is identical to passage 186 in section 114, and is raised upward through hose section 145 and through nozzle 144 into pumping tube 120 in section 116. The liquid then passes upwardly out of nozzle 146, through hose section 148 and through nozzle 150 in joining section 114 into pumping tube 120 of joining section 114. The liquid is thus raised through the pumping tube 120 of joining sections 116 and 114, and through hose section 148, by means of a bubble released in the joining section below joining section 116, andalso by means of suction applied to pumping tube 120 in joining section 114 through vacuum port 152, which has a plug 154 disposed directly above it.

The liquid then fiows laterally through passage 156 into chamber 158, the upper portion of which is disposed within joining section 114. The upper end of chamber 158 is defined by a plug 160, and the lower portion of chamber 158 consists of a nozzle 162 at the bottom of joining section 114, a hose section 164 which connects nozzle 162 to a nozzle 166 at the top of joining section 116, and a portion of chamber 158 in joining section 116 which has its bottom defined in reservoir tube 118 by plug 140.

The liquid then flows laterally out of chamber 158 to the left through passage 168 in joining section 116 into pumping tube 122 of joining section 116, the liquid then being lifted upward by a bubble released from vacuum relief port 172 in tube 170 which is operatively connected to vacuum tube 126 in joining section 116. The liquid flows upward through nozzle 174, hose section 176, nozzle 178, and pumping tube 122 in joining section 114, the liquid passing upward out of joining section 114 through a nozzle 180 and hose section 181.

The next joining section above joining section 114 is identical to joining section 116, with a vacuum port similar to vacuum port 132 to assist in raising the liquid. The bottom portion of the next reservoir chamber 184 is connected to the joining section above joining section 114 by hose section 185 and nozzle 182, and the liquid from reservoir chamber 184 passes laterally to the right, through passage 186 in joining section 114 into pumping tube 120, the liquid then being raised in part by bubbles released at vacuum relief port 190 which is operatively connected to vacuum tube 124 in joining section 114 through a tube 188. This liquid then flows upward out of joining section 114 through nozzle 192 and hose section 193 into the next joining section above section 114.

Although it will be noted that the preferred embodiment of my invention illustrated in Figures 1 to 4 utilizes six tu'bes, two of which are vacuum tubes 38 and 40, in the preferred form of my alternative embodiment of Figures and 6 I utilize only five hose sections between successive joining sections, such as the five hose sections 148, 164, 176, 194 and 196 between joining sections 114 and 116. The use of only five sections to join the adjacent. joining sections in my alternative embodiment of Figures 5 and 6 is accomplished by utilizing only a single vacuum tube in each of the joining sections, and using opposite vacuum tubes in adjacent joining sec-' tions. Thus, vacuum tube 126 is used in joining section 116, and vacuum tube 124 is used in joining section 114, with hose section 194 operatively connecting vacuum tube 126 of joining section 116 with vacuum tube 124 of joining section 114. Vacuum tube 124 of joining section 116 is idle, and also vacuum tube 126 of joining section 114 is idle.

If it is desired, an extra hose section may be used to connect adjacent joining sections, and a separate hose section may be used to connect tubes 124 of adjacent joining sections, while a separate hose section is used to connect tubes 126 of adjacent joining sections. This additional, sixth hose section is desirable if the liquid is to be pumped to relatively great heights, as friction is diminished in the vacuum tubes by this means.

The successive joining sections, such as sections 114 and 116, of my alternative embodiment are preferably approximately 8 feet apart, although they may be spaced at wider intervals.

Ordinary hose can be used to connect adjacent joining sections in my alternative embodiment, so that the structure necessary to produce my pump may be sold as a. plurality of joining sections 114 and 116 which are appropriately marked to permit the purchaser to opcr atively connect the successive joining sections with hose to produce his own pump string of any desired length. Plastic tubing may be used in place of the hose, with rubber adapters being used to connect this tubing to the respective joining sections if it is desired.

This use of successive joining sections coupled together by hose sections has the additional advantages of cheapness to manufacture and of compactness in storage, the integrated pump string being sufiiciently flexible to be rolled onto a drum for storage and the entire pump string being readily disassembled to its component parts.

It is to be understood that the form of my invention herein shown and described is my preferred embodiment and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of my appended claims.

I claim:

1. A vacuum pump string including a reservoir having an elongated chamber therein, said chamber having an upper and a lower flow passage, a tube operatively connected to said reservoir and extending downwardly from said upper flow passage, means communicating with said downwardly extending tube near its upper end for creating a partial vacuum in the upper end of said downwardly extending tube, a tube operatively connected to said reservoir and extending upwardly from said lower flow passage, and means communicating with said upwardly extending tube near its upper end for releasing bubbles in said upwardly extending tube near the lower end thereof.

2. A vacuum pump string including a reservoir having an elongated chamber therein, said chamber having an upper and a lower flow passage, a tube operatively connected to said reservoir and extending downwardly from said upper fiow passage, a tube operatively connected to said reservoir and extending upwardly from said lower flow passage, means communicating with said upwardly extending tube near its lower end for releasing bubbles in said upwardly extending tube near the lower end thereof, and means communicating with both of said tubes near their upper ends for creating a partial vacuum in the upper ends of both of said tubes.

3. A vacuum pump string including a reservoir having an elongated chamber therein, said chamber having an upper and a lower flow passage, a tube operatively connected to said reservoir and extending downwardly from said upper flow passage, a vacuum tube, an operative connection between said vacuum tube and the upper end of said downwardly extending tube, a tube, operatively connected to said reservoir and extending upwardly from said lower flow passage, a bubble release port in said upwardly extending tube near the lower end thereof, a vacuum relief tube, and an operative connection between said vacuum relief tube and said bubble release port.

4. A vacuum pump string including a reservoir having an elongated chamber therein, said. chamber having an upper and a lower flow passage, a, tubeoperatively connected to said reservoir and extending downwardly from said upper flow passage, a tube operatively connected to said reservoir and extending. upwardly'from said lower flow passage, a bubble release port in said: upwardly extending tube near the lower end. thereof, a vacuum pump having gas input and output ports, an operative connection between said gas inputport and the upper ends of both of said tubes, and an operative connection between said output port and said bubble releaserport.

5. A vacuum pump string including a reservoir having an elongated chamber therein, said chamber having an upper and a lower flow passage, a tube operatively connected to said reservoir and extending downwardly from said upper flow passage, means communicating with said downwardly extending tube near its upper end for creating relatively low pressure in the upper end of said downwardly extending tube, a tube operatively connected to said reservoir and extending upwardly from said lower flow passage, said means communicating with said upwardly extending tube near its lower end for releasing bubbles in said upwardly extending tube near the lower end thereof, said reservoir and said tubes consisting in part of a hose section and a portion of a hose joining section.

6. A vacuum pump string including a plurality of reservoirs disposed one above the other, each of said reservoirs having an elongated chamber therein, a lower and an upper flow passage in each of said chambers, a tube connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher chamber, said tube being operatively connected to the respective said reservoir, means communicating with each of said tubes near its upper end for creating relatively low pressure in the upper end of each of said tubes, and means communicating with each of said tubes near its lower end for releasing bubbles in each of said tubes near the lower end of that tube.

7, A vacuum pump string including a plurality of reservoirs disposed one above the other, each of said reservoirs having an elongated chamber therein, a lower and an upper flow passage in each of said chambers, a connecting tube connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher chamber, said connecting tube being operatively connected to the respective said reservoirs, a vacuum tube, means for maintaining a partial vacuum in said vacuum tube, an operative connection between said low pressure tube and the upper end of each of said connecting tubes, and means operatively connected to each of said tubes near its lower end for releasing bubbles in each of said tubes near the lower end of that tube.

8. A vacuum pump string including a plurality of reservoirs disposed one above the other, each of said reservoirs having an elongated chamber therein, a lower and an upper flow passage in each of said chambers, a connecting tube connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher chamber, said connecting tube being operatively connected to the respective said reservoirs, a vacuum tube, means for maintaining a partial vacuum in said vacuum tube, an operative connection between said vacuum tube and the upper end of each of said connecting tubes, a bubble release port in each of said connecting tubes near the lower end of that connecting tube,

a, vacuum relief tube, and an operative connection be: tween said vacuum relief tube and. each of said bubble release ports. I

9, A vacuum pump string including a, reservoir. tube containing a plurality of spi'aced plugs to providefa plurality of elongated chambers disposed one above the other, a lower andan upper now. passage in each said chambers, a. plurality: of pumping tubes, each con.-

, taining a plurality of spaced plugs. to. provide a plu:

rality of connecting tubes, one of .said connecting tubes connecting, the lower flow passage of eachaofsaid chamv bers, withtheupper flow passage of the next: higher chamber, means communicating with each. of said connecting tubes near its upper endfor creating, relatively low pressure in the upper end of each of saidconnect: ing tubes, and means communicating with each of said connecting tubes near its lower end for; releasing} hubbles-in eachof said connectingitubesnear the. lower; en

of that, connecting. tube.

10. A vacuum pump string including a reservoir tubecontaining a plurality of spaced plugs to provide a plurality of elongated chambers disposed one above the other, a lower and an upper flow passage in each of said cham bers, a plurality of pumping tubes each containing a plurality of spaced plugs to provide a plurality of connecting tubes, one of said connecting tubes connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher chamber, a vacuum tube, means operatively connected to said low pressure tube for maintaining a sub-atmospheric pressure in said vacuum tube, an operative connection between said vacuum tube and the upper end of each of said connecting tubes, a bubble release port in each of said connecting tubes near the lower end of that connecting tube, a vacuum relief tube, and an operative connection between said vacuum relief tube and each of said bubble release ports.

11. A vacuum pump including a reservoir tube containing a plurality of spaced plugs to provide a plurality of elongated chambers disposed one above the other, a lower and an upper flow passage in each of said chambers, a plurality of pumping tubes each containing a plurality of spaced plugs to provide a plurality of connecting tubes, one of said connecting tubes connecting the lower flow passage of each of said chambers with the upper flow. passage of the next higher chamber, a vacuum tube, an operative connection between said vacuum tube and the upper end of each of said connecting tubes, a vacuum relief port in each of said connecting tubes near the lower end of that connecting tube, a vacuum relief tube, an

operative connection between said vacuum relief tube and each of said vacuum relief ports, a vacuum pump having gas input and output ports, and operative connections between said input and output ports and the upper ends of said vacuum and pressure relief tubes, respectively, to provide a closed gas system for said pump.

12. A vacuum pump string including a plurality of reservoirs disposed one above the other, each of said reservoirs having an elongated chamber therein, a lower and an upper flow passage in each of said chambers, a tube connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher cham ber, means communicating with each of said tubes near its upper end for creating a partial vacuum in the upper end of each of said tubes, and means communicating with each of said tubes near its lower end for releasing bubbles in each of said tubes near the lower end of that tube, each of said reservoirs and tubes consisting in part of a hose section and a portion of a hose joining section.

13. A vacuum pump string including a plurality of reservoirs disposed one above the other, each of said reservoirs having an elongated chamber therein, a lower and an upper flow passage in each of said chambers, a tube connecting the lower flow passage of each of said chambers with the upper flow passage of the next higher ass-1,3,1?

Qh mbq avacuum t m ans ormai ai ng pa tial vacuum in said vacuum tube, an operative connec-j tion'between' said low pressure tube and the upper end of g each of said connecting tubes, a vacuum relief port in each of said connecting tubes near the lower end of that connecting tube, a vacuum relief tube, and an operativ'e connection between said vacuum relief tube andeach of said vacuum relief ports, each of said reservoirs and tubes consisting in part of a hose section and a portion of a hose joining section. V

' 14. A vacuum pump string including a plurality of reservoirs-disposed one above the other, each of said feservoirs having an elongated chamber therein, a lower and an upper flow passage in' each of said chambers, a tube connecting the lower fiow passage of each of said chambers with the upper flow passage of the next higher chamber, means communicating with each of said tubes near its upper end for creating relatively low pressure in the upper end of each 'of said tubes and means communicating with each of said tubes'near its-lower end for 12 releasing bubbles in each ofsaid tubes near the lower end of that tube, each of said reservoirs and tubes consisting in part of a hose section and a portion of a hose joining section, each of said hose joining sections containing one 'of said upper flow passages and one of said lower flow passages.

References Cited in the file of this patent UNITED STATES PATENTS 536,858 Donato Apr. 2, 1895 559,810 Rand May 12, 1896 753,045 Cooper Feb. 23, 1904 827,341 Young et a1. July 31, 1906 899,921 Stephenson Sept. 29, 1908 960,023 Knight May 31, 1910 1,102,152 Jones -u June 30, 1914 1,537,264 Rogers May 12, 1925 1,628,943 Wolcott May 17, 1927 Feb, 8, 

